Abstract

In order to address the issue of whether neon liquid in coexistence with its gas phase can be mapped to a quantum Lennard-Jones (LJ) fluid, we perform a series of simulations using Gibbs ensemble Monte Carlo for a range of de Boer quantum parameters . The quantum effects are incorporated by implementing the variational Gaussian wavepacket method, which provides an efficient numerical framework for estimating the quantum density at thermal equilibrium. The computed data for the LJ liquid is used to produce its phase diagram as a function of the quantum parameter, 0.065 ⩽ Λ ⩽ 0.11. These data are then used to fit the experimental phase diagram for neon liquid. The resulting parameters, ε = 35.68 ± 0.03 K and σ = 2.7616 ± 0.0005 Å (Λ = 0.0940), of the LJ pair potential are optimized to best represent liquid neon in coexistence with its gas phase for a range of physically relevant temperatures. This multi-temperature approach towards fitting and assessing a pair-potential is much more consistent than merely fitting a single data point, such as a melting temperature or a second virial coefficient.

Received 24 December 2012Accepted 08 March 2013Published online 01 April 2013

Acknowledgments:

The authors would like to thank the reviewers for their suggestions and A. Z. Panagiotopoulos for fruitful discussions. This work was supported by the National Science Foundation (NSF) (Grant No. CHE-1152845). I.G. was supported in part by NSF (Grant No. DMS-1101578).